

I’m not sure this true - PDF is an open standard. The issue isn’t generally with layout and reproducibility - a good PDF maker and a good reader will give you an accurate representation of how it looks on all devices once the PDF is created.
Certainly there isn’t a dedicated FOSS tool for make PDFs; Libre Office and Inkscape do a decent job but not perfect which may be what you’re referring to. And they’re not dedicated PDF makers plus the real problem is building fillable forms and signature tools.
But there is a proprietary alternative called Master PDF that is a dedicated and supports all the PDF standard features I believe; one perpetual license is $80 compared to Adobe subscription based charging. I’m not aware of other options myself but they may exist. But it’s a viable alternative to the “adobe tax”.
Also of course if you have Office 365 from Microsoft, you can use Word to export docs to PDF reliably (in my experience). Obviously as far as you can get from FOSS, but it is an option on Linux via web browser if you have it from work for example; at least you don’t have to pay Adobe but it’s scraping the bottom of the barrel for this threat I know!
Others have pointed out what may he going wrong (drive locked due to Windows fast startup).
A slightly different tack - dual booting windows and linux on the same drive is a bad idea. One reason is the messy boot set up which can cause issues with windows not booting or linux not booting, or either/both fighting over the boot partition. It can get to the point of using repair disks to repair one or the other or both. It can be managed but make a mistake and its a real headache to fix (I say that as someone who has been their and done that and learned the lesson)
If you want to switch to linux but keep windows “just in case” and have a desktop I’d get a new SSD and use it as a dedicated linux drive. SATA or even better an m.2 card if your motherboard has the slots.
A separate drive is far better as linux can be the drive booted by the BIOS and then Grub can then point back to your untouched windows drive to boot it when you want. If linux updates it won’t affect windows, and if windows updates it won’t affect linux. Also if you have a drive failure you won’t lose 2 OSes and all data in one go.
Personally I have 5 drives in my PC - easy expansion of storage is a big benefit to a nice full size PC. I have one largely unused windows drive, and 4 ext4 drives.